Projection type image display device

Abstract

A projection type image display device comprising: a projection optical system having a first refracting optical section having a plurality of lenses, a reflecting optical section having at least one concave reflecting surfacer and a second refracting optical section in order from a reduction side; and an image forming optical section disposed on an anterior stage of a light path as the reduction side of the projection optical system, wherein the second refracting optical section has an exit lens having either: (1) a roughly constant thickness and disposed in a posterior stage of the light path from an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape convex towards the magnification side; or (2) a roughly constant thickness and disposed between the reflecting optical section and an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape concave towards the magnification side.

1. A projection type image display device comprising:
 a projection optical system having a first refracting optical section having a plurality of lenses, a reflecting optical section having at least one concave reflecting surface, and a second refracting optical section in order from a reduction side; and 
 an image forming optical section disposed on an anterior stage of a light path as the reduction side of the projection optical system, 
 the second refracting optical section having an exit lens having either:
 (1) a roughly constant thickness and disposed in a posterior stage of the light path from an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape convex towards the magnification side, or 
 (2) a roughly constant thickness and disposed between the reflecting optical section and an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape concave towards the magnification side, 
 
 the second refracting optical section being formed of the exit lens as a meniscus lens, and 
 assuming a curvature radius of a convex surface of the exit lens of the second refracting optical section is R1, and a curvature radius of a concave surface of the exit lens is R2, the following condition (2) is satisfied:
   0.7 <R 2 /R 1<1.1  (2).
 
 
 
     
     
       2. The projection type image display device according to  claim 1 ,
 the meniscus lens having a pair of spherical optical surfaces, and an optical axis identical to the optical axis of the reflecting optical section. 
 
     
     
       3. The projection type image display device according to  claim 1 ,
 the meniscus lens having a domed shape with a concentric sphere shape having a center of curvature of the lens surface in the vicinity of the exit pupil position. 
 
     
     
       4. The projection type image display device according to  claim 1 ,
 the meniscus lens having an optical axis decentered with respect to the optical axis of the reflecting optical section. 
 
     
     
       5. The projection type image display device according to  claim 1 ,
 at least one of the pair of optical surfaces of the meniscus lens being formed of an aspheric surface. 
 
     
     
       6. The projection type image display device according to  claim 1 ,
 the meniscus lens being formed from a resin material. 
 
     
     
       7. The projection type image display device according to  claim 1 ,
 an optical axis common to at least a part of the magnification side of the first refracting optical section and the reflecting optical section extending perpendicular to a screen for projection. 
 
     
     
       8. The projection type image display device according to  claim 1 ,
 further assuming that a curvature radius of the reflecting surface of the first refracting optical section is Ra, the following condition (1) is satisfied:
   0.2 <|R 1 /Ra|< 2.0  (1).
 
 
 
     
     
       9. The projection type image display device according to  claim 1 ,
 further assuming a a distance between the exit pupil position and a position at which the principal ray intersects with the concave surface of the exit lens is S, the following condition (3) is satisfied:
   0.3 <S/R 2<1.5  (3).
 
 
 
     
     
       10. A projection type image display device comprising:
 a projection optical system having a first refracting optical section having a plurality of lenses, a reflecting optical section having at least one concave reflecting surface, and a second refracting optical section in order from a reduction side; and 
 an image forming optical section disposed on an anterior stage of a light path as the reduction side of the projection optical system, 
 the second refracting optical section having an exit lens having either:
 (1) a roughly constant thickness and disposed in a posterior stage of the light path from an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape convex towards the magnification side, or 
 (2) a roughly constant thickness and disposed between the reflecting optical section and an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape concave towards the magnification side, 
 
 the second refracting optical section being formed of the exit lens as a meniscus lens, and 
 assuming that a curvature radius of the reflecting surface of the first refracting optical section is Ra, and a curvature radius of a convex surface of the exit lens of the second refracting optical section is R1, the following condition (1) is satisfied:
   0.2 <|R 1 /Ra|< 2.0  (1).
 
 
 
     
     
       11. A projection type image display device comprising:
 a projection optical system having a first refracting optical section having a plurality of lenses, a reflecting optical section having at least one concave reflecting surface, and a second refracting optical section in order from a reduction side; and 
 an image forming optical section disposed on an anterior stage of a light path as the reduction side of the projection optical system, 
 the second refracting optical section having an exit lens having either:
 (1) a roughly constant thickness and disposed in a posterior stage of the light path from an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape convex towards the magnification side, or 
 (2) a roughly constant thickness and disposed between the reflecting optical section and an exit pupil position at which a principal ray reflected by the reflecting surface and proceeding towards the maximum field angle and the optical axis of the reflecting optical section intersect with each other, and an optical surface of a magnification side of the exit lens has a shape concave towards the magnification side, 
 
 the second refracting optical section being formed of the exit lens as a meniscus lens, and 
 assuming a curvature radius of a concave surface of the exit lens of the second refracting optical section is R2, and a distance between the exit pupil position and a position at which the principal ray intersects with the concave surface of the exit lens is S, the following condition (3) is satisfied:
   0.3 <S/R 2<1.5  (3).